We will send an object with the following start and end properties as on the example below:

// just an example schema of
// const reorder = action.payload
// so you can see what values are sent to the DASHBOARD_REORDER_ITEM
this.props.reorderItem({
start: this.state.draggedItemIndex,
end: droppedItemId
})

The start is a set of numbers in the dashboardItems array. The end property is an order number of a dropped-on-the-item h4 block (the id of an item that a user dropped on the dragged item). The rest of the code shall be self-explanatory.

Changes in (you can click the diffs image to make it larger):
src/routes/Dashboard/containers/DashboardContainer.js

Changes in (you can click the diffs image to make it larger):
src/routes/Dashboard/components/Dashboard.js

Changes in (you can click the diffs image to make it larger):
src/components/Dashboard/Dashboard.js

The most important part to understand this code above is that the h4 block has an id as a number (check the code from the src/components/Dashboard/Dashboard.js which is listed below) and that number is an order in the new array that is kept in the dashboard reducer.